The present invention relates to a computer controllable display system and in particular to the interaction of a user with a computer controlled image display or projected image.
Computer controlled projection systems generally include a computer system for generating image data and a projector for projecting the image data onto a projection screen. Typically, the computer controlled projection system is used to allow a presenter to project presentations that were created with the computer system onto a larger screen so that more than one viewer can easily see the presentation. Often, the presenter interacts with the projected image by pointing to notable areas on the projected image with their finger, laser pointer, or some other pointing.
The problem with this type of system is that if a user wants to cause any change to the projected image they must interact with the computer system using an input device such as a mouse, keyboard or remote device. For instance, a device is often employed by a presenter to remotely control the computer system via infrared signals to display the next slide in a presentation. However, this can be distracting to the viewers of the presentation since the presenter is no longer interacting with them and the projected presentation and, instead, is interacting with the computer system. Often, this interaction can lead to significant interruptions in the presentation.
Hence, a variation of the above system developed to overcome the computer-only interaction problem allows the presenter to directly interact with the projected image. In this system, the computer system generates image data (e.g. presentation slides) to be projected onto a screen (e.g. projection screen) with an image projector device. The system also includes a digital image capture device such as a digital camera for capturing the projected image. The captured projected image data is transmitted back to the computing system and is used to determine the location of the an object in front of the screen such as a pointing device. The computer system may then be controlled dependent on the determined location of the pointing device. For instance, in U.S. Pat. No. 5,138,304 assigned to the assignee of the subject application, a light beam is projected onto the screen and is detected by a camera. To determine the position of the light beam, the captured image data of the projected image and the original image data are compared to determine the pointer position. The computer is then caused to position a cursor in the video image at the pointer position or is caused to modify the projected image data in response to the pointer position.
In order to implement a user interactive, computer controlled display or projection system, an initial calibration step is necessary where the computer system determines the location of the screen or more specifically the area in which the image is displayed within the capture area of the camera. By determining the location of the display area within the capture area, the system can then identify any object that is not part of the displayed image (e.g., objects in front of the displayed image). In one prior art system, the location of the display area within the capture area is determined by using complex, and sometimes fragile, pattern matching algorithms requiring a significant amount of computing time and system memory usage.
The present invention is an efficient, robust, and simple technique for locating an image display area within the capture area of an image capture device in a user interactive, computer controlled display or projection system.
A system for locating an user interactive, computer controlled image display area includes a display area for displaying a plurality of selected digital images, a computing system for providing digital image data for causing the plurality of selected digital images to be displayed, an image capture device having an image capture area for capturing a plurality of images within the capture area each including one of the selected digital images, and a display area locator including a means for deriving constructive or destructive feedback data from digital image data corresponding to the plurality of captured images to determine the location of the display area within the image capture area.
The method for determining the location of the user interactive, computer controlled display area within an image capture area of an image capture device is performed by displaying a plurality of selected images in the display area, capturing a plurality of images within the capture area each including one of the plurality of selected images, and deriving constructive or destructive image feedback data from the image data corresponding to the plurality of captured images in order to locate the display screen in the image capture area of the image capture device.